Abraham Lincoln concluded his first Inaugural Address in 1861 by expressing confidence that the "better angels" of the American psyche would one day prevail over racism. But as the country prepares to inaugurate its first black President on Jan. 20, new academic evidence suggests that the demons of unconscious racism still hold startlingly powerful sway.

A study in the Jan. 9 issue of the journal Science presents strong evidence that even people who aspire to tolerance  who would consider themselves nonracist  still harbor unconscious biases powerful enough to prevent them from confronting overt racists or from being upset by other people's racist behavior. The authors say the results suggest attitudes so deeply ingrained that protective legislation and affirmative-action programs are required to overcome them. The results may even offer clues as to how other societies have spiraled into genocide.

The study, by researchers at Yale University and Toronto's York University, involved 120 nonblack students who were told they were being recruited for an experiment on team-oriented problem-solving. They were broken into three groups. The members of the first group were individually placed in a room with a black actor and a white actor, both posing as fellow participants in the study, and watched as the black actor slightly bumped the white actor while leaving the room. After the black actor had left, the white actor played out one of three scenarios, saying, "I hate it when black people do that," "Clumsy n______" or nothing at all. None of the people in the two other study groups experienced the interactions directly; one group watched them on video and the other simply read about them. (See The Cure for Racism.)

After the incident, students were asked to choose one of the two actors  still posing as fellow participants  for the teamwork assignment. More than 80% of the students who watched a racist exchange on video said they would not work with the white student. Those who read about racist behavior showed a similar aversion, with 75% preferring the black actor as a teammate. Participants in both groups said they were deeply upset by the racist comments.

The same did not hold true for the participants who experienced the racist event firsthand. None intervened to correct or disparage the white actor, nor did they report being upset by his comments when questioned later. In fact, 71% of the students chose the white actor as their partner for the assignment when he made a racist comment; a similar percentage chose the white partner when he did not make a racist comment.

The study's authors speculate that people who witnessed the event in person were less offended by the racist behavior because of a psychological phenomenon known as the impact bias of affective forecasting, which is the tendency for people to overestimate how strongly they will react to emotional events. Failing to feel outrage, the participants may have then rationalized the racist comment as somehow acceptable and let it pass, the researchers say.

"People expect to feel much more emotion than they actually do. We are good at rationalizing responses," says Jack Dovidio, a Yale psychologist and co-author of the study. "If there are certain costs  we don't want to get involved, maybe because we aren't quite as committed to equality as we thought we were  then we go through a series of rationalizations: 'Maybe it wasn't that bad.' That's the danger  that we explain everything away. It justifies our behavior."

"I think this helps explain the big discrepancy in [North American] culture between what people say and think about racism and the actual persistence of racism in our society," he says. (The study's participants were students in Toronto, but Dovidio says the results reflect North American, rather than strictly Canadian, biases.)

The study, titled "Mispredicting Affective and Behavioral Responses to Racism," adds to the emerging but still controversial "implicit association" theory of racism. Researchers have long known that people hold culturally instilled associations with certain objects  English-speaking North Americans are faster to recognize the word butter if they have just seen the word bread momentarily flashed on a screen (ditto soy and rice for East Asians). Harvard psychologist Mahzarin Banaji has found that Americans recognize negative words such as angry, criminal and poor more quickly after being exposed to a black face (often blacks do too), suggesting unconscious racist associations with black people.

But some psychologists have questioned the link between unconscious racist attitudes and real-world discrimination. In an Op-Ed piece in the Wall Street Journal in 2005, Philip Tetlock, a psychologist at the University of California, Berkeley, and Amy
Wax, a law professor at the University of Pennsylvania, mocked the notion that "we are all racists at heart," claiming that "no research demonstrates that, after subtracting the influence of residual old-fashioned prejudice, split-second reactions in the laboratory predict real-world decisions."

Dovidio says his study provides strong evidence to the contrary and argues that tacit acceptance of racism is enough to influence outcomes in a society. "The most worrying aspect is that even if a small proportion of a society is active, old-fashioned racists, and if the majority of people who believe they are not racist rationalize away racist behavior and don't intervene or even get upset when it occurs, then the society is going to be an unfair, unequal society," Dovidio says. Kerry Kawakami, a co-author of the study at York University, goes even further, claiming it shows how societies can degrade into genocide: "The results may explain how Nazi Germany happened."

Dovidio and Kawakami say the study suggests North Americans need help, in the form of regulations such as workplace quotas and affirmative action, if they expect to realize their egalitarian ideals. "We shouldn't push policies that focus on intentions but rather on outcomes," Dovidio says.

He adds that similarly executed "deception studies," in which experimenters withhold disclosure about the nature of the experiment to participants, have revealed troubling examples of human callousness before. It was studies in the 1970s, he points out, that identified the psychological phenomenon of "diffusion of responsibility," which gained notoriety following the brutal public slaying of Kitty Genovese in New York City in 1964, during which none of her neighbors in the surrounding apartment buildings responded to her cries for help or called the police.

But Dovidio says that unconscious biases can be overcome through self-awareness as North Americans learn to free blacks from the negative associations that have metaphorically fettered them for so long. As a measure of the difficulty of allowing our better angels to prevail, however, consider this question: Do you imagine those angels to be black?